Ohlins makes a Bike GT-R...MCN Rides

Discussion in 'Motorcycles' started by Jim Prower, Jul 8, 2009.

  1. Jim Prower

    Jim Prower Premium

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    Interesting...Hydraulic 2WD. It's certainly lighter than most other systems so far, (What's there been? the Rokon?) and torque split could even be achieved in the future (vary the displacement of the pump, it's ridiculously easy)...Could...maybe...we soon see the bike equivalent of Godzilla?
     
    Last edited: Jul 8, 2009
  2. Dragonistic

    Dragonistic

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    My question is simply, why? Why would you want 2 wheel drive over RWD?
     
  3. ANFD

    ANFD

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    Because it's easier to do wheelies with the front wheel spinning in the air ... gyro effect :dopey:

    Only kidding, although true :)
     
  4. Jim Prower

    Jim Prower Premium

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    I assume that it's the same reason they'd want the 4WD in a sportscar: to get more power to the ground. launch of corners better and the like. I'll have to wait for MCN to publish some riding impressions to see how they think, and if it's really worth it, but it is lightweight this time 'round...hoping that, perhaps, it's durable enough to go all-out for extended periods of time.

    I just found it some interesting engineering, but you may take it as you will.
     
  5. PAPPACLART

    PAPPACLART

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    Because in some instances there coould a performance and saftey improvement, like when it is wet or the road is badly serviced. As a motorcycle rider I definately welcome the idea of 2WD motorcycles:tup:
     
  6. Dragonistic

    Dragonistic

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    I still think a bad surface that would throw a rider on 1WD will still send them off with 2WD. The most common fall is probably at low speed on low grip surfaces caused by rain or whatever, when the bike simply slips from under you as you simply turn with little/no throttle. I also can't see a 2WD handling better, I mean I know I wouldn't want my front tyre to be under any more pressure then what I've put it through, is there not more chance of losing front traction if it's dealing with power as well? I can see a benefit for enduros for off-roading, thats clear but for a road bike? I'm not so sure. It just seems like something to go wrong either mechanically or causing accidents through overloading the front tyre. Do you really want bike understeer, because it's a hell of a lot more frightening to me when my bike understeers then when the rear gets loose, infact I feel extremely comfortable when the rear hangs out but when the front lets go I fear for my life.
     
  7. wfooshee

    wfooshee Premium

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    ^^^^^ Kind of my questions.

    Front slide = FEAR!!!!

    Back slide = correct and continue. (At least until it gets to 20 or 30 degrees out of line, then it's back to FEAR!!!!)

    FEAR!!!! usually equals CRASH!!!!!!

    Pics of aftermath of gravel stealing front wheel from me:
    [​IMG]

    [​IMG]


    I'm wondering if a 2WD bike would need a bit more tire at the front. Not quite another rear because of the weight balance, but more than we use currently. That one seemed to have a standard front tire.

    I haven't seen any rider impressions, just that video. The video tells us nothing about what the bike's doing that it couldn't do before.

    OTOH hand, I don't ride dirt bikes. and I don't ride 10/10ths, so I really couldn't say what a little power from the front end would do for me.
     
  8. Dragonistic

    Dragonistic

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    Looks like you suffered similar damage to when I came off my bike at a whopping.... 20mph. Few scratches on the helmet, some bumps and bruises and a slightly scratched front mud guard. Wet road + bad surface = uh oh! I tried to turn and it was just like falling in slow motion, I knew I was going but it was to late to do anything about it but brace and hope. The handlebars somehow ended up massively crooked (I had to ride a little up the road to a clear spot and my handlebars were about 20 degrees off) I feared I'd bent the forks but it looked like they were ok so we took the entire front end apart, put it back together and it was perfect. I wasn't even touching the throttle or anything ilke that and my tyres are pretty similar front and back already (supermoto sports tyres). I believe this is the way most riders fall, I know of little sensible riders who care about safety that would be saved by 2WD seeing as most major (and indeed minor) accidents there's no throttle involved when the accident occurs.
     
  9. Keef

    Keef Premium

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    Seems dangerous. Understeer is catastrophic on a motorcycle like Wfooshee said, and powering the front wheel would only reduce it's available grip to make a turn. That's one reason why you get understeer with a car.

    Because this is a hydraulic system I'm curious if the front wheel would decelerate the same as the rear when you let go of the throttle, as if it were mechanically attached to the engine. But it's not mechanically attached. There could be some sort of fluid bypass when the engine starts decelerating so that the front wheel would freewheel. It already seems you'd have to be careful with the front brake while entering a corner at speed, but if the front wheel starts slowing simply by letting of the gas it would complicate the problem.
     
    Last edited: Jul 9, 2009
  10. PAPPACLART

    PAPPACLART

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    I am not sure how you work that out? The system offers approx 30bhp to the front wheel and really does not have enough shove to cause any under steer; actually it is likely to assist the cornering ability of a bike by pulling the bike through a corner.

    What causes a traditional motorcycle to underster is when it exits a corner hard on the power, causing the back end to squat the front to lift which leaves less weight on the front tyre limiting available grip, not to mention the geometry changes because of the squatting. Bikes of course can under steer on corner entry too but this will not affected by a 2wd system due to there being on most cases no need to accelerate into a corner.
     
  11. wfooshee

    wfooshee Premium

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    Yeah, I was 20mph tops, still a little clutch in first gear coming out of a hairpin. Just didn't look through far enough and got a surprise for my mistake.

    As for how we work that out, it's the very thing you pointed out. Getting on the power lifts the front wheel, makes it lighter. Now you want to apply power with that lightened load? Wheelspin is a possibility, although the hydraulic system is not supposed to drive the wheel any faster than the tranny output, so the front shouldn't spin unless the rear's slipping, too. Nevertheless, it could overwhelm the friction circle if you're too close to the edge of it.

    Comparing to to FWD or AWD in a car isn't quite valid for a couple of reasons. First, because there's no diff, so no way the front takes more torque than it's fed by the hydraulics. That makes a nice limit to the system, and yet if the front gets light enough, the drive force can pull it to the outside harder than an undriven wheel, and you'll lose the front end. Second, because there's less steering angle. Don't think of it as pulling to the inside like a car's wheel, which is steered. Remember that a bike's front end is very close to straight ahead, the turning comes from the lean. If you want to turn harder, the front wheel actually gets steered the other way. You push down on the bar toward the way you want to go, and the countersteer induces lean. If the front wheel is pulling, it will widen the turn. That's the very definition of understeer.

    As for drag at the front end when the throttle closes, I would really hope the thing freewheels, kind of like a torque converter in a car.
     
    Last edited: Jul 10, 2009
  12. Jim Prower

    Jim Prower Premium

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    Well, it COULD be possible to vary the displacement of the pump/motor system quite easily. Simply put a movable swashplate in there, and you vary the amount that the pistons move. Vary displacement, you should vary torque transmitted. I.E. Zero Displacement, Zero torque, Max Displacement, Max torque.

    I'm starting to think, though, that they may be testing this system to see how durable it is under ridiculously high speeds before they offer it to off-road riders over the market.